Cromwell



UNITED STATES PATENT OFFICE.

CROMlVELL 0. CASE, OF NEWV BRITAIN, CONNECTICUT, ASSIGNOR TO P. & F.

' CORBIN, OF SAME PLACE.

DOOR-KNOB.

SPECIFICATION forming part of Letters Patent No. 409,010, dated August 13, 1889.

Application filed May 16, 1889. Serial No. 310,968- (No model.)

To to whom it may concern:

Be it known that I, CROMWELL 0. CASE, a citizen of the United States, residing at New Britain, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Cast-Metal Door- Knobs, of which the following is a specification.

My invention relates to improvements in hollow cast-metal door-knobs; and the chief object of my invention is to produce a substantial hollow knob in which the parts are firmly forced and held together.

In the accompanying drawings, Figure 1 is a vertical section of the parts composing my knob, the same being placed together without being secured; and Fig. 2 is alike view of my knob in its finished form.

The general form of the knob is old, con- 2o sisting of the ordinary oval form as viewed in the drawings, and when viewed in end view of the ordinary round form.

A designates one part of the shell, provided with the ordinary knob-shank B, the shell portion consisting of a cup or saucer shaped part with a plain edge in the ordinary form for such parts.

C designates the cap portion of the shell, which I provide with the ordinary flange 3, 0 for being turned down upon the exterior of the part A 'in the ordinary manner. In addi-' tion to these ordinary parts I provide the cap C with an internal flange 4, leaving an annular space between the flanges 3 and 4 for the 3 5 edge of the part A to set into. The .flange 4 should be of such a size and project on as to extend somewhat into the interior of the part A and snugly fill the same. The parts are then put in alathe or special machine, firmly held together therein, and the flange 3 bent or spun firmly down upon the part A, as shown in Fig. 2. The cap C being formed of cast metal, a powerful pressure is required in order to spin down the flange 3 so as to set it firmly against the part A and make a close joint. The internal flange 4 holds the edge of the part A in place and prevents it from bending inwardly under the diametrical pressure of the spinning-tool, whereby I am enabled to firmly force the parts together, so as to form a firm union and a close joint by pressure.

I am aware that a knob ofsubstantially the same general character as the one herein shown, without the internal flange 4 and the annular space defined on the inside by said flange, is old, and such a knob is hereby disclaimed.

I claim as my invention- The herein-described door-knob, consisting of an ordinary half-shell A and knob-shank B, and the cap part C of the shell, provided with the internal flange 4 and ordinary extern al flange 3, and an annular space between said flanges, into which the edge of the halfshell A sets, substantially as described, and for the purpose specified.

CROMIVELL 0. CASE.

lVitnesses:

A. N. ABBE, CHARLES F. CORBIN. 

